Few layers graphene based conductive composite inks for Pt free stainless steel counter electrodes for DSSC

Abstract

FTO and platinum free steel counter electrode substrate based dye-sensitized solar cells (DSSC) are fabricated with few layers graphene (FLG) composite conductive inks. FLG are synthesized by liquid phase high shear exfoliation and the FLG based composite conducting inks are formulated with multi walled carbon nanotubes (MWCNT) and carbon black (CB) in polyimide matrix. The developed ink formulations are suitable for high temperature processing at 500 degrees C which enables to form graphene based composite conducting films on steel. Polyamic acid (PAA) intermediate layer provides superior adherence and potentio-dynamic polarization studies suggest that PAA coating also provides barrier layer and passivates the corrosion rate. Dye sensitized solar cells have been fabricated with these graphene composite coated on steel substrates which serves as the back electrodes. The cyclic voltammetry (CV) results of FLG composite conductive ink coated steel shows encouraging catalytic activity for the redox reaction of I-/I-3(-) redox mediator. The developed FLG based composite ink formulations and fabrication of working DSSCs with conducting graphene composite coated steel substrate can be a potential step towards the realization of Pt free large area roof top DSSCs